Methods for insulation fault location and the devices (insulation fault location devices) implementing these methods are known from the state of the art and are used for locating insulation faults in power supply systems, in particular for determining the faulty cable outlet in the event of a first (insulation) fault occurring in an ungrounded network.
Should an insulation fault occur in the ungrounded power supply system, it will initially be identified and reported by an insulation monitoring device. This report initiates the insulation fault location by the insulation monitoring device or by an insulation fault test apparatus, which as part of an insulation fault location device can also be realized as an insulation fault test device, producing a test current and supplying the test current into the power supply system. This test current signal is detected by all measuring current transformers, which are arranged in the faulty electric circuit having the faulty cable outlet, and evaluated and displayed via an insulation fault evaluation device. The faulty cable outlet can be determined by assigning the measuring current transformer to the electric circuit or rather the cable outlet.
The cable outlet in the branched power supply system having the insulation fault is then identified, although the exact position of the insulation fault on this faulty cable outlet is still not known.
In order to quickly repair the insulation fault, however, knowing the exact fault position on the faulty cable outlet is useful.